The present invention relates generally to a system for controlling a signal-measuring instrument using a displacement mechanism and, more specifically, to a microprocessor controlled system where said mechanism is a rotary knob.
Many electronic mesurement instruments include microprocessor systems for improving signal measurement functions. In certain of these instruments, key switches are used to set measurement conditions, to control data display scrolling operations, or to enter alphanumeric data such as labels. Sometimes one or more keys, (e.g., increment and decrement keys) are used to alter a parameter setting or data value, or to control the scrolling operation, each depression of the key causing a predetermined next data value, parameter setting, or address (location) to be displayed. Usually when a key is held down, successive changes in data values or locations are made to occur at a predetermined fixed rate of progression. Often this causes "overshoot", where the equipment setting has progressed to a point beyond the desired setting value or location, obliging the user to initiate the setting process again, and to progress more slowly to the desired setting. Typically the progression rate chosen is either too slow to move conveniently through a large number of setting values or acquired data, or too fast to properly examine each value or data location. Such instruments usually also require the use of a full typewriter-like keyboard, complete with shift key for entry of alphanumeric data.
As control systems, these instruments are generally quite complex, underscoring the need for simpler systems capable of performing data entry and parameter setting operations.